Questions tagged [odds-ratio]
A measure of association between two binary variables equal to the odds of a 'positive' outcome in 1 variable divided by the odds in the other. The OR ranges (0, infinity). It has a strong connection to logistic regression.
1
vote
0answers
11 views
How does fisher.test calculate the confidence interval for the odds ratio in R?
The fisher.test function in base R by default returns a confidence interval for the odds ratio in a 2x2 contingency table. For example:
...
0
votes
1answer
15 views
Strange odds ratio (OR) derived from Fisher's test
I have frequency data for about 1000 genetic marker for two groups that I want to compare them between the two groups. I used Fisher’s test (in R) on the count data and got FDR and odds ratio (OR) for ...
0
votes
0answers
16 views
Creating a Weighted Ratio Based On Size of Customer
I am attempting to created a weighted ratio/score for customers based on the number of support tickets they have entered in a time period against the number of units they have in service with us.
...
0
votes
0answers
24 views
1D Bayesian Inference clarification
I'd like some help making sure I understand a 1D Bayesian inference problem.
Say I have a data vector which is an array of the number of flu cases reported weekly in California for the past 10 years.
...
0
votes
0answers
5 views
predict important markov chains(paths to an event) with confidence
I need help in validating my current approach as well as find any alternative approaches I could use in order to tackle issues like below.
I have a dataset like below and I need to find important ...
2
votes
1answer
51 views
Odds ratio not between the two odds ratio of a stratified analysis
This is not the first time I have performed stratified analyses based on logistic regressions, but I have never before been confronted with this situation.
When I test my relationship in the overall ...
2
votes
0answers
38 views
Odds Ratio, More Likely vs. As Likely, do I need to subtract 1?
When reporting odds ratios from a logistic regression, I've seen the words "as likely" and "more likely." If the odds ratio is say 3.5, I know that I can say females are 3.5 times as likely as males ...
0
votes
0answers
9 views
How to compare odds ratios across stratified sub-groups
From a randomized controlled trial, I have odds ratios (ORs) of disease A for an intervention vs control group.
I want to see if the OR differs according to deprivation.
I plan to stratify my study ...
1
vote
0answers
34 views
Interpretation of two odds ratios derived from two different cohen's ds, comparability for meta-analysis?
I have a question regarding the conversion of cohen's d into odds ratio (OR) and the comparability of results from two different situations. I wonder if the ORs derived from the two situations can ...
0
votes
0answers
8 views
reversal of odds ratios in covariate adjusted model
I am using a survey weighted GLM in R for a binary outcome. The raw risk ratio and the unadjusted ORs suggest that group 2 has significantly lower risk/odds. In the covariate adjusted model, the ...
0
votes
1answer
22 views
Converting OR to probabilities
I'm trying to understand some of my data in a logistic regression. I plotted headache (yes/no) vs. age and get an OR of 0.95.
Now I realize this means that for every year 'younger', you have a 0.95 ...
0
votes
0answers
24 views
Conclusion for not rejecting a null hypothesis
I'm actually quite confused what is the outcome we could deduce here for the other exercise types listed in the diagram.
From my interpretation, the null-hypothesis is: There is no association ...
2
votes
1answer
28 views
How does non-response bias affect the Confidence Interval
I asked earlier what is the idea behind putting up Table 3.
I have a follow up question on how non-response bias identified can justify the different sizes of Confidence Interval(CI) in Figure 3. My ...
0
votes
1answer
12 views
The effect of a lack of dose-response results on odds ratio
This is part of a quantitative reasoning assignment I was working on.
The study hypothesized that exercise may reduce the risk of disability for activities of daily living(ADL). However after ...
0
votes
1answer
19 views
Deriving the values of the range around the mean value
This is part of a bigger quantitative reasoning assignment I was working on.
My understanding here is that the upper bound and lower bound of the ranges for each of the exercises should be reflected ...
1
vote
2answers
118 views
How do I interpret the odds ratio of an interaction term in Conditional Logistic Regression?
I am wondering what the correct interpretation of the odds ratio of an interaction term in conditional logistic regression is.
Let's say there are two independent variables A and B, as well as an ...
0
votes
0answers
8 views
ODDS RATIO, NNT CONFUSION
I'm really confused.
I have 3 drugs and the following odds ratios were retrieved -
A 1.71 (95% CI=1.25-2.33)
B 1.58 (95% CI=1.12-2.22)
C 1.48 (95% CI=1.12-1.95)
These values were generated with ...
0
votes
0answers
22 views
Comparing adjusted odds ratios in a model
I have a pretty basic question. Say I run a logistic regression model with 2 variables both dichotomous. falls= sex+stroke+depression. I get 3 different odds ratios, one for males vs females, one for ...
0
votes
1answer
24 views
How to interpret OR confidence intervals for interaction or confounding?
This is a textbook problem I've been trying to understand I wanted to check if my thinking is correct (unfortunately there is no solution manual) I have a case-control study where I'm looking at ...
1
vote
1answer
23 views
COMPARISONS OF ODDS RATIOS
For example, if I have 3 different trials each for 3 different drugs and I used meta analysis (sub group analysis) to generate effect sizes. How can I interpret the effect sizes? All drugs are being ...
0
votes
0answers
36 views
Do small odds ratios observed at multiple time points equate to a large odds ratio when averaged across time points?
I am testing the relative odds of two groups, placebo vs active treatment, guessing that they received active treatment. These guesses were made at four time points, 4, 8, 12, and 24 weeks into a ...
0
votes
0answers
77 views
How to manually calculate odds ratio for continuous variables?
In school, long before learning about logistic models, I've been taught how to calculate odds ratios by hand.
Formula was based on a contingency table, just like this:
This is very easy to ...
0
votes
1answer
28 views
Re-calibrating Intercept on logistic regression models for unbalance data
I have data-set that I’m modelling using logistic regression as land.cover~H1+H2+H3+H4+H6+H8+H14. My response and categorical variables are binary. However the number of 0 and 1 in my response ...
3
votes
0answers
24 views
Why is information gain rarely used as a reported effect size?
Commonly, in reporting effect sizes in medical articles, papers typically report: risk difference (RD), relative risk (RR) and odds ratio (OR) (and for variable timescale cases and other situations, ...
0
votes
0answers
19 views
How to compute (and report correctly) the signifiance of interaction effect on categorical data, using logistic regression
I want to study the odds of success and failure at some test, depending on gender and some other categorical variables. I calculated the Odds Ratios (OR) of success using Logistic Regression, with « ...
0
votes
1answer
40 views
Odds Ratio Vs. Risk Ratio
Relative risk, odds ratio, risk ratio, risk difference - these are all measures of the direction and the strength of the association between two categorical variables.
Can I use any of these four ...
1
vote
1answer
89 views
Connection between Hazard Ratios, Survival, and Probability
According to this wiki link, the hazard ratio relates to survival according to the following equation
$$
S_1(t)=S_0(t)^r \quad (1)
$$
where $S$ is the survival and $r$ is the hazard ratio. So from ...
0
votes
0answers
10 views
Using log odds ratio to compare bigram frequency between 2 profiles
I was reading an article where the author proposed using the log odds ratio calculation to compare the relative frequency of bigrams between 2 websites. From my understanding the odds ratios are used ...
1
vote
0answers
16 views
What is the interest to implement a statistics model in a groupby object instead of use the whole groups in a sample?
I saw this topic and also this one in dask documentation.
I wonder what is the real interest to make a model for each group instead of considering a whole sample where all groups would appear? As far ...
0
votes
0answers
8 views
Are effect sizes calculated for prospective/ retrospective cohort studies that look at odds ratios?
Are effect sizes calculated for prospective/ retrospective cohort studies that look at odds ratios? I apologise if this is a silly question
1
vote
0answers
21 views
Is this the correct way to interpret odds ratio for three way interaction?
grateful for any thoughts about this.
I'm doing a generalized linear model analysis of a binomial dependent variable (whether the participant gets the correct answer or not).
I have three ...
1
vote
1answer
35 views
Can I use odds ratio in Google trends?
I want to compare the popularity of several fish types:
The way I'm doing it is by using a reference keyword (in this case "fish") and comparing it to whatever fish I'm interested in.
I enter both ...
2
votes
0answers
29 views
How to generate samples from joint distribution of normal and logistic with R?
How to generate triple data $(Y,R,X)$ with R code satisfying following restrictions:
$X \sim N(0,1)$, $R$ is binary and $P(r=1\mid y=0,x) = expit(\alpha_0+\alpha_1 x)$. $Y$ is continuous and $Y\mid r=...
0
votes
1answer
178 views
Odds Ratio from Linear Regression?
Maybe a stupid question, but can I calculate Odds Ratio's from a linear regression model?
Or is it only possible / allowed on a logistic model?
(I have a linear mixed-effects model and I use r and ...
0
votes
0answers
36 views
Calculating odds ratio in Multiple select choice question analysis
I have a multiple response categorical variable (MRCV) and a single response categorical variable (SRCV). Respondents in my survey were presented with 6 choices (6 barriers to access an application) ...
1
vote
0answers
221 views
How do I get an odds ratio with McNemar's test?
I have pre and post test data evaluating the effectiveness of a lesson about how to help friends who are being bullied. I am trying to see if more students know how to help a friend being bullied ...
0
votes
0answers
110 views
How to calculate the odds ratio if one of the groups is “0” in a case-control study?
I am using R's epicalc package to calculate the odds ratio. I have these data:
Real values
...
6
votes
1answer
175 views
Where is my mistake in this definition of Bayes Factor?
From "The Bayesian Choice" by Christian P. Robert.
The definition of the Bayes factor is given to be the ratio of the posterior probabilities of the null and the alternative hypothesis over the ratio ...
1
vote
0answers
29 views
How does one compute the posterior odds ratio between two models
Apologies if this question has been asked before but I couldn't find anything that matched my problem.
I have some astronomy based data sets and wish to find which of three models fits the data the ...
1
vote
3answers
346 views
Computation and Interpretation of Odds Ratio with continuous variables with interaction, in a binary logistic regression model
Question
A binary logistic regression model has been fitted, with the following output;
...
1
vote
2answers
27 views
Odds ratio? Can someone help me with what these stats from a paper mean?
this paper I'm reading is on MAOA and violent offenders. From what I understand, an odds ratio of 1.71 means that the violent offenders were almost 2x likely to exhibit the low activity MAOA compared ...
1
vote
0answers
138 views
Conditional logistic regression on matched data with replacement
I'm using 1 to 5 matching on my data with replacement, where each treatment is paired to at most 5 control units with the possibility of one control unit being assigned to more than one treatment.
...
2
votes
1answer
57 views
Adjusted odds ratio question
I have a question about adjusted odds ratios for matched data. Let's assume that we have a binary variable that we want to determine the odds ratios for (let's say smoking or not smoking, this is the ...
2
votes
2answers
130 views
17 Week Coin Flip Contest - Calculate Probability/Odds For Each Individual To Have The Winning Count Of “Heads”
I'm new to statistics, like WAY new. So green, in fact, I'm scarcely pushing (0,1,0) in the RGB color model.
I'm presently the recordkeeper for our office's 17-week "Coin flip pool". As of right now, ...
13
votes
1answer
270 views
Is meta-analysis of odds ratios essentially hopeless?
In a recent paper Norton et al. (2018)$^{[1]}$ state that
Different odds ratios from the same study cannot be compared when the
statistical models that result in odds ratio estimates have ...
1
vote
0answers
18 views
Can we compare odds ratio from one factor to another factor?
For example ${\rm logit}(\pi)=\beta_1 \cdot x_1+ \beta_2 \cdot x_2$, then I find that the odds ratio of $x_2$ is 27, and the odds ratio of $x_1$ is 1.5, can I say that $x_2$ has a more significant ...
3
votes
1answer
62 views
Difficulty understanding contingency table and logistic regression coefficient
I have the following contingency table
D not-D
E 980 122
not-E 2420 6439
where D may stand for disease, and E for exposure.
This leads to the ...
2
votes
1answer
26 views
Difference in logits to difference in probabilities
a) Is there any way to prove that you cannot compute a probability difference when you know a logit difference?
b)In general, is there some acceptable way to convert distances in logodds space to ...
0
votes
1answer
98 views
Odds ratio, Meta-analysis
I have the following for the data for the meta-analysis:
OR , standard errors, logged OR , variance of logged OR
I have generated a forest plots first using "OR" with "variance of logged OR" using ...
0
votes
1answer
69 views
Betting with odds
I have a game where I can bet on two teams:
One team has odds $1.7$
The other has $1.5$
I understood that the one that pays off $1.5$ has an higher probability of victory, so it pays less. But how ...
